title: [Phenotypic properties of Escherichia coli K-12 purine auxotrophs with disordered synthesis of guanine, xanthine and hypoxanthine phosphoribosyltransferases].
abstract: Purine auxotrophs of Escherichia coli completely blocked for reutilization of guanine, xanthine and hypoxanthine via phosphoribosiltransferase reactions (purD hpt gpt) were studied. They lost the ability to utilize inosine as the source of carbon and purines though retained the purine nucleoside phosphorilase activity. The bacteria of this genotype were also found to be sensitive to leucine, despite the presence of relA+ allele. These phenotypic properties of the purD hpt gpt bacteria were suppressed by the introduction of cya mutation which affects cAMP synthesis into their genome. It has been shown that exogenous cAMP inhibits growth of purD hpt gpt (cya+) bacteria and this has been considered to suggest that purD hpt gpt cya bacteria have an increased pool of purine nucleotides as a consequence of a decrease in the catabolite-sensitive genes activity.
mesh_terms: D004790:Enzyme Induction; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D007041:Hypoxanthine Phosphoribosyltransferase / Q000096:biosynthesis* / Q000235:genetics; D010430:Pentosyltransferases / Q000096:biosynthesis* / Q000235:genetics; D010641:Phenotype; D011687:Purines / Q000378:metabolism*
chemical_list: D011687:Purines; D010430:Pentosyltransferases; C024827:xanthine phosphoribosyltransferase; D007041:Hypoxanthine Phosphoribosyltransferase
vernacular_title: Fenotipicheskie svoĭstva purinovykh auksotrofov Escherichia coli K-12 s narushennym sintezom fosforiboziltransferaz guanina, ksantina i gipoksantina.